battery chargers, again
in [Design]
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From: krw on 2 Oct 2009 20:12 On Fri, 02 Oct 2009 07:09:34 -0700, Joerg <invalid(a)invalid.invalid> wrote: >John Larkin wrote: >> On Thu, 01 Oct 2009 14:06:36 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >> >>>> The layout is tedious, because we're optimizing the BGA FPGA routing >>>> as we go along... can't just draw the schematic and go forward to the >>>> board. >>>> >>> Ouch. >>> >>> >>>> This *is* rev 30. >>>> >>> Double-Ouch. I am firing up rev 1 of a really unorthodox cicuit this >>> afternoon. Wish me luck, and if you hear a muffled boom north-east from >>> you guys ... >> >> Was that an earthquake or was the Joerg? >> > >No, it worked, must have been an earthquake then ;-) > > >> To calarify, this is rev 30 of the working layout. We haven't fabbed >> any boards yet. >> >> The PCB file will be formally released as 26D150A.PCB, to make rev A >> of the product. During layout, we number every iteration. If we change >> a net or add a resistor or whatever, we start with schematic >> 26S150A29.SCH, change it to 26S150A30.SCH and save that, make the >> differences file ECO30, apply that onto pcb 26D150A29.PCB, and save as >> 26D150A30.PCB. So we have all the iterations and all the ECO files, >> all organized. When we release the schematic and pcb as rev A, we >> delete all that working junk. Since we're iterating on the BGA pinout, >> we're spinning a lot of ECOs. >> >> If we go A to B, we start the sequence all over, 26S150B1.SCH etc. >> > >I do it similarly, except adding X1, X2 and so on. And I usually cannot >erase the intermediates upon ECO-release because federal agencies often >require that a complete design history be kept. So if you do medical, >maybe better not to toss it. A *complete* design history down to the placement of each wire sounds excessive. But what the heck, disks are cheap these days.
From: John Larkin on 2 Oct 2009 20:21 On Fri, 02 Oct 2009 07:09:34 -0700, Joerg <invalid(a)invalid.invalid> wrote: >John Larkin wrote: >> On Thu, 01 Oct 2009 14:06:36 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >> >>>> The layout is tedious, because we're optimizing the BGA FPGA routing >>>> as we go along... can't just draw the schematic and go forward to the >>>> board. >>>> >>> Ouch. >>> >>> >>>> This *is* rev 30. >>>> >>> Double-Ouch. I am firing up rev 1 of a really unorthodox cicuit this >>> afternoon. Wish me luck, and if you hear a muffled boom north-east from >>> you guys ... >> >> Was that an earthquake or was the Joerg? >> > >No, it worked, must have been an earthquake then ;-) > > >> To calarify, this is rev 30 of the working layout. We haven't fabbed >> any boards yet. >> >> The PCB file will be formally released as 26D150A.PCB, to make rev A >> of the product. During layout, we number every iteration. If we change >> a net or add a resistor or whatever, we start with schematic >> 26S150A29.SCH, change it to 26S150A30.SCH and save that, make the >> differences file ECO30, apply that onto pcb 26D150A29.PCB, and save as >> 26D150A30.PCB. So we have all the iterations and all the ECO files, >> all organized. When we release the schematic and pcb as rev A, we >> delete all that working junk. Since we're iterating on the BGA pinout, >> we're spinning a lot of ECOs. >> >> If we go A to B, we start the sequence all over, 26S150B1.SCH etc. >> > >I do it similarly, except adding X1, X2 and so on. And I usually cannot >erase the intermediates upon ECO-release because federal agencies often >require that a complete design history be kept. So if you do medical, >maybe better not to toss it. The next logical step would be to log every key and mouse click, and videotape everything that happens in Engineering. John
From: Spehro Pefhany on 2 Oct 2009 21:09 On Fri, 02 Oct 2009 16:54:18 -0700, the renowned Joerg <invalid(a)invalid.invalid> wrote: >krw wrote: >> On Fri, 02 Oct 2009 08:08:08 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote: >> >>> On Fri, 02 Oct 2009 07:59:11 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>> [snip] >>>> Just got assembled boards back from AA-PCB yesterday. They threw in a >>>> bag of trail mix. Sweet. Needless to say, it was all gone before I had >>>> the first scope shots on the server and I wasn't too hungry at dinner time. >>> Funny what extraneous stuff can end up in a shipment. Recently found >>> a chocolate chip 2-pack in my Amazon order ;-) >> >> You guys must be buying crummy product. > > >Nah, they did a great job. And the trail mix was really good. Maybe K. meant "crumby"? ;-) Why would I name a pet salamander "Tiny"? Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff(a)interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
From: krw on 2 Oct 2009 23:18 On Fri, 02 Oct 2009 21:09:57 -0400, Spehro Pefhany <speffSNIP(a)interlogDOTyou.knowwhat> wrote: >On Fri, 02 Oct 2009 16:54:18 -0700, the renowned Joerg ><invalid(a)invalid.invalid> wrote: > >>krw wrote: >>> On Fri, 02 Oct 2009 08:08:08 -0700, Jim Thompson >>> <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote: >>> >>>> On Fri, 02 Oct 2009 07:59:11 -0700, Joerg <invalid(a)invalid.invalid> >>>> wrote: >>>> >>>> [snip] >>>>> Just got assembled boards back from AA-PCB yesterday. They threw in a >>>>> bag of trail mix. Sweet. Needless to say, it was all gone before I had >>>>> the first scope shots on the server and I wasn't too hungry at dinner time. >>>> Funny what extraneous stuff can end up in a shipment. Recently found >>>> a chocolate chip 2-pack in my Amazon order ;-) >>> >>> You guys must be buying crummy product. >> >> >>Nah, they did a great job. And the trail mix was really good. > >Maybe K. meant "crumby"? ;-) Why would I name a pet salamander >"Tiny"? Homonym shomonym.
From: JosephKK on 3 Oct 2009 09:20
On Sun, 27 Sep 2009 21:16:46 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >Last time a car went dead in the garage, my wife's Fit, I hacked up a >charger from an old DSL wall-wart and a sabre saw as a series current >limiter. The garage geometry makes it essentially impossible for us to >push a car uphill to the street to jump it. Now The Brat left her Echo >in the garege for a month or so and it went dead, too. So I figure >it's time to buy a real charger. Went to Kragen Auto Parts and bought >two (one for here, one for Truckee) chargers. They are all "smart >chargers", namely switchers with electronics, these days. > >The battery is really dead, 1.8 volts. The first charger hums and >outputs nothing. Tried the next one: it hummed for maybe 3 seconds >then sparked and smoked inside. > >Went back to Kragen and traded up, two better chargers. Neither >charges... no current, battery steady at 1.8 volts. Both have their >"charging" LEDs off and "charge complete" LEDs lit. > >Back to Kragen, 3rd time, got all my money back. Passed by Bob Pease's >place all three trips, same collection of rusty VWs everywhere. > >A charger that puts zero amps into a dead battery does that by design, >and there's only one reason to do that: to convince people they need a >new battery. Kragen's sales pitch was exactly along those lines; "Tt >won't charge, so all the cells are shorted." > >So I went to work and nabbed a cute little Lascar bench power supply. >It current limits at 1.2 amps, so I just cranked it up. The battery >went instantly to 16.5 volts, then settled down to 12 or so in a few >minutes, and is creeping back up. > >Interesting. > >So I guess I'll buy a couple of 3 amp or so lab supplies, with nice >volt and amp meters, instead of battery chargers. They're handier to >have around anyhow, cost about the same as a "good" charger, and >aren't booby trapped. > >What Kragen is doing is fraud. > >John What is the sound of one hand clapping? |